CASCACascade Atlas

Evidence dossier

CVE-2025-35939

Craft CMS stores user-provided content in session files

Exploited in the wild (CISA KEV since Jun 2, 2025). cisa-cg reports CVSS 4.0 6.9. EPSS estimates 1.3% exploit likelihood as of Aug 27, 2026.

62.2–63.7Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

Craft CMS stores arbitrary content provided by unauthenticated users in session files. This content could be accessed and executed, possibly using an independent vulnerability. Craft CMS redirects requests that require authentication to the login page and generates a session file on the server at '/var/lib/php/sessions'. Such session files are named 'sess_[session_value]', where '[session_value]' is provided to the client in a 'Set-Cookie' response header. Craft CMS stores the return URL requested by the client without sanitizing parameters. Consequently, an unauthenticated client can introduce arbitrary values, such as PHP code, to a known local file location on the server. Craft CMS versions 5.7.5 and 4.15.3 have been released to address this issue.

State
PUBLISHED
Published
May 7, 2025
Updated
Feb 26, 2026
Evidence coverage
95%

Evidence chronology

What was known when

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  1. Source dateSource date omittedFirst observed by CASCA
    CISA-ADP

    Record text: CISA ADP Vulnrichment

    Inspect raw assertion
    Field
    container
    Value
    CISA ADP Vulnrichment
    Original evidence ↗
  2. Source dateSource date omittedFirst observed by CASCA
    cisa-cg

    Record text: Craft CMS stores user-provided content in session files

    Inspect raw assertion
    Field
    container
    Value
    Craft CMS stores user-provided content in session files
    Original evidence ↗
  3. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Craft CMS External Control of Assumed-Immutable Web Parameter Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Craft CMS External Control of Assumed-Immutable Web Parameter Vulnerability
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 1.32% probability · 68.71th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.013170000000; percentile 0.687090000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Jun 2, 2025 · first observed Jul 19, 2026

Exploit likelihood1.32%

FIRST EPSS · score date Aug 27, 2026 · 68.7th percentile · first observed Aug 27, 2026

SeverityCVSS 6.9

cisa-cg · CVSS 4.0 · first observed Jul 19, 2026 · same-version scores align in this snapshot

Evidence detail

Source limits and decisions

Why each evidence state has this value

casca-unknown-reasons-v1
Exploitation statusEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Aug 27, 2026
Resolution
None
Exploit likelihoodEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Aug 27, 2026
Resolution
None
Severity assessmentEvidence supported

Eligible evidence is present for this bounded claim.

Revision
casca-direct-cvss-eligibility-v1
Cutoff
Aug 27, 2026
Resolution
None
Affected productsSource-reported scope

The cited source assertion is retained while canonical product linkage remains open.

Revision
casca-factor-d-obligations-v1
Cutoff
Aug 27, 2026
Resolution
Resolve identity

Source comparison

Who said what

CISA-ADPIndependent enrichment
Record text

CISA ADP Vulnrichment

Inspect raw assertion
Field
container
Value
CISA ADP Vulnrichment
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
cisa-cgOriginal assertion
Record text

Craft CMS stores user-provided content in session files

Inspect raw assertion
Field
container
Value
Craft CMS stores user-provided content in session files
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

Craft CMS External Control of Assumed-Immutable Web Parameter Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Craft CMS External Control of Assumed-Immutable Web Parameter Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

1.32% probability · 68.71th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.013170000000; percentile 0.687090000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
2Underlying assertions
1Canonical products
2Target assertions
0Constraint assertions

Grouped from 1 configuration nodes in this exact snapshot. Visual grouping is navigational; asset exposure and root cause require cited evidence.

Identity source boundaries
  • Cpe dictionary1,775,266 records · observed through 2026-07-21T06:45:29.809Z27d65b0f-b718-4b4f-bb79-c47c68d09dfa
  • Cpe match643,502 records · observed through 2026-07-21T08:13:17.697Z955dae73-7302-438b-aee1-058d7cc5d48e

2 scope groups

cisa-cg · source assertedCraftCMSDirect source scope
Affected: 0 to before 5.7.5 (custom comparison)Unaffected: 5.7.5Affected: 0 to before 4.15.3 (custom comparison)Unaffected: 4.15.3
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "0", "lessThan": "5.7.5", "versionType": "custom"}, {"status": "unaffected", "version": "5.7.5"}, {"status": "affected", "version": "0", "lessThan": "4.15.3", "versionType": "custom"}, {"status": "unaffected", "version": "4.15.3"}]
NVD CPE · APPLICATIONcraftcmscraft_cmsVulnerable target · 2 assertions
Any version (unconstrained) (< 4.15.3); Any version (unconstrained) (>= 5.0.0, < 5.7.5)Canonical identity product-652086c7824312f8c27d52e3a413a9a70922a5b06b0e37ab334d67cee861ece6Linked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:a:craftcms:craft_cms:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 1
    Logic
    OR
    Version bounds
    from including 5.0.0; through excluding 5.7.5
    Match ID
    61bca33b-aea5-45aa-a757-9348c48a4728
  2. cpe:2.3:a:craftcms:craft_cms:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    through excluding 4.15.3
    Match ID
    8c8b256d-000b-4588-8182-cec2acc076eb

Affected-product evidence

Accepted scope and product mapping

1 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-dff06628f19630b48001e5732c23df2c03a0ebb17559b1a14bb6e367a6b3f6fb · product-652086c7824312f8c27d52e3a413a9a70922a5b06b0e37ab334d67cee861ece6

Source class
Nvd cpe vulnerable target
Assertions
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
87691baa-43bb-4701-a270-e4192048fcf2cb2e6637-579d-44f3-9016-f3d8042d31a4
Source-reported scopeSource-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Vendor specified only by source · Product specified only by source

Source class
Direct cve affected
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
c7d6bae5-181d-4e15-8f69-38c52d78e8ec

Assessments

CVSS by origin

5.3
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
6.9
CVE Program sourceCVSS 4.0 · role Secondary · priority eligiblevalid_matchCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
5.3
CVE Program sourceCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
6.9
cisa-cgCVSS 4.0 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
5.3
cisa-cgCVSS 3.1 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Direct CVE/CNA normalized decisions

6.9Priority eligible

cisa-cg

CVSS 4.0 · Primary · Original assertion · rank 1

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Validation
Valid match
Recomputed
6.9
Decision reason
Evidence supported
Policy
casca-direct-cvss-eligibility-v1
5.3Priority eligible

cisa-cg

CVSS 3.1 · Primary · Original assertion · rank 1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Validation
Valid match
Recomputed
5.3
Decision reason
Evidence supported
Policy
casca-direct-cvss-eligibility-v1

Assessments are retained side by side under closed precedence. Cascade never averages CVSS.

Evidence boundaries

  • KEV membership is authoritative for the catalog, not proof of exposure in any environment.
  • EPSS is a dated model probability and not an individual-environment prediction.
  • Affected or fixed status applies only to the exact cited product and version scope; remaining scope stays source-scoped.
  • NVD-carried upstream facts remain derivative; independent corroboration requires a separately authored source.
  • Only NVD metrics validated under the generation-bound calculator are Public Priority eligible; direct CVE record metrics remain display-only.
  • NVD CVSS source eligibility is closed: NVD-authored, exact record-source, or registered same-CVE container origin; unmapped sources remain display-only.
  • Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.
  • OSV aggregation and OSV-converted NVD material are not independent corroboration.
  • Red Hat facts are vendor assertions for the exact supplied products.
  • Nonmembership and not-yet-observed states are not proof of safety.